The present invention relates to compounds, processes for their synthesis, compositions and methods for the treatment of hepatitis C virus (HCV) infection. In particular, the present invention provides novel peptide analogs, pharmaceutical compositions containing such analogs and methods for using these analogs in the treatment of HCV infection.
Hepatitis C virus (HCV) is the major etiological agent of post-transfusion and community-acquired non-A non-B hepatitis worldwide. It is estimated that over 200 million people worldwide are infected by the virus. A high percentage of carriers become chronically infected and many progress to chronic liver disease, so-called chronic hepatitis C. This group is in turn at high risk for serious liver disease such as liver cirrhosis, hepatocellular carcinoma and terminal liver disease leading to death.
The mechanism by which HCV establishes viral persistence and causes a high rate of chronic liver disease has not been thoroughly elucidated. It is not known how HCV interacts with and evades the host immune system. In addition, the roles of cellular and humoral immune responses in protection against HCV infection and disease have yet to be established. Immunoglobulins have been reported for prophylaxis of transfusion-associated viral hepatitis, however, the Center for Disease Control does not presently recommend immunoglobulins treatment for this purpose. The lack of an effective protective immune response is hampering the development of a vaccine or adequate post-exposure prophylaxis measures, so in the near-term, hopes are firmly pinned on antiviral interventions.
Various clinical studies have been conducted with the goal of identifying pharmaceutical agents capable of effectively treating HCV infection in patients afflicted with chronic hepatitis C. These studies have involved the use of interferon-alpha, alone and in combination with other antiviral agents. Such studies have shown that a substantial number of the participants do not respond to these therapies, and of those that do respond favorably, a large proportion were found to relapse after termination of treatment.
Until recently, interferon (IFN) was the only available therapy of proven benefit approved in the clinic for patients with chronic hepatitis C. However the sustained response rate is low, and interferon treatment also induces severe side-effects (i.e. retinopathy, thyroiditis, acute pancreatitis, depression) that diminish the quality of life of treated patients. Recently, interferon in combination with ribavirin has been approved for patients non-responsive to IFN alone. However, the side effects caused by IFN are not alleviated with this combination therapy. Pegylated forms of interferons such as PEG-Intron(copyright) and Pegasys(copyright) can apparently partially address these deleterious side-effects but antiviral drugs still remain the avenue of choice for oral treatment of HCV.
Therefore, a need exists for the development of effective antiviral agents for treatment of HCV infection that overcome the limitations of existing pharmaceutical therapies.
HCV is an enveloped positive strand RNA virus in the Flaviviridae family. The single strand HCV RNA genome is approximately 9500 nucleotides in length and has a single open reading frame (ORF) encoding a single large polyprotein of about 3000 amino acids. In infected cells, this polyprotein is cleaved at multiple sites by cellular and viral proteases to produce the structural and non-structural (NS) proteins. In the case of HCV, the generation of mature nonstructural proteins (NS2, NS3, NS4A, NS4B, NS5A, and NS5B) is effected by two viral proteases. The first one, as yet poorly characterized, cleaves at the NS2-NS3 junction (henceforth referred to as NS2/3 protease); the second one is a serine protease contained within the N-terminal region of NS3 (NS3 protease) and mediates all the subsequent cleavages downstream of NS3, both in cis, at the NS3-NS4A cleavage site, and in trans, for the remaining NS4A-NS4B, NS4B-NS5A, NS5A-NS5B sites. The NS4A protein appears to serve multiple functions, acting as a cofactor for the NS3 protease and possibly assisting in the membrane localization of NS3 and other viral replicase components. The complex formation of the NS3 protease with NS4A seems necessary to the processing events, enhancing the proteolytic efficiency at all of the sites. The NS3 protein also exhibits nucleoside triphosphatase and RNA helicase activities. NS5B is a RNA-dependent RNA polymerase that is involved in the replication of HCV.
A general strategy for the development of antiviral agents is to inactivate virally encoded enzymes that are essential for the replication of the virus.
The following is a list of patent applications published in the last few years that disclose HCV NS3 protease inhibitor peptide analogs that are structurally different from the compounds of the present invention:
GB 2,337,262; JP10298151; JP 11126861; JP 11292840; JP 2001-103993; U.S. Pat. No. 6,159,938; U.S. Pat. No. 6,187,905; WO 97/43310; WO 98/17679; WO 98/22496; WO 98/46597; WO 98/46630; WO 99/38888; WO 99/50230; WO 99/64442; WO 99/07733; WO 99/07734; WO 00/09543; WO 00/09558; WO 00/20400; WO 00/59929; WO 00/31129; WO 01/02424; WO 01/07407; WO 01/16357; WO 01/32691; WO 01/40262; WO 01/58929; WO 01/64678; WO 01/74768; WO 01/77113; WO 01/81325; WO 02/08187; WO 02/08198; WO 02/08244; WO 02/08251; WO 02/08256; WO 02/18369; WO 02/60926 and WO 02/79234.
One advantage of the present invention is that it provides tripeptide compounds that are inhibitory to the NS3 protease, an enzyme essential for the replication of the hepatitis C virus. Furthermore, the compounds are able to inhibit HCV RNA replication in the replicon cell model.
A further advantage of one aspect of the present invention resides in the fact that the compounds specifically inhibit the NS3 protease and do not show significant inhibitory activity against other serine proteases such as human leukocyte elastase (HLE), porcine pancreatic elastase (PPE), or bovine pancreatic chymotrypsin, or cysteine proteases such as human liver cathepsin B (Cat B).
Included in the scope of the invention is a compound of formula (1): 
wherein R1 is hydroxy or NHSO2R1A wherein R1A is (C1-8)alkyl, (C3-7)cycloalkyl or {(C1-6)alkyl-(C3-7)cycloalkyl}, which are all optionally substituted from 1 to 3 times with halo, cyano, nitro, Oxe2x80x94(C1-6)alkyl, amido, amino or phenyl, or R1A is C6 or C10 aryl which is optionally substituted from 1 to 3 times with halo, cyano, nitro, (C1-6)alkyl, Oxe2x80x94(C1-6)alkyl, amido, amino or phenyl; R2 is (C4-6)cycloalkyl; R3 is t-butyl or (C5-6) cycloalkyl and R4 is (C4-6)cycloalkyl; or a pharmaceutically acceptable salt thereof.
Included within the scope of this invention is a pharmaceutical composition comprising an anti-hepatitis C virally effective amount of a compound of formula I, or a therapeutically acceptable salt thereof, in admixture with a pharmaceutically acceptable carrier medium or auxiliary agent.
According to one embodiment, the pharmaceutical composition of this invention further comprises interferon (pegylated or not), or ribavirin, or one or more other anti-HCV agent, or any combination of the above.
Another important aspect of the invention involves a method of treating a hepatitis C viral infection in a mammal by administering to the mammal an anti-hepatitis C virally effective amount of a compound of formula I, a pharmaceutically acceptable salt thereof, or a composition as described above, alone or in combination with one or more of: interferon (pegylated or not), or ribavirin, or one or more other anti-HCV agents, administered together or separately, e.g., prior to, concurrently with or following the administration of the compound of formula I or pharmaceutically acceptable salt thereof.
Another important aspect of the invention involves a method of preventing a hepatitis C viral infection in a mammal by administering to the mammal an anti-hepatitis C virally effective amount of a compound of formula I, a pharmaceutically acceptable salt thereof, or a composition as described above, alone or in combination with one ore more of: interferon (pegylated or not), or ribavirin, or one or more other anti-HCV agents, all of which administered together or separately, e.g., prior to, concurrently with or following the administration of the compound of formula I or pharmaceutically acceptable salt thereof.
Also within the scope of this invention is the use of a compound of formula I, as described herein, for the manufacture of a medicament for the treatment or prevention of hepatitis C viral infection.
The present description refers to a number of documents, the content of which is herein incorporated by reference.
As used herein, the following definitions apply unless otherwise noted:
With reference to the instances where (R) or (S) is used to designate the absolute configuration of a substituent or asymmetric centre of a compound of formula 1, the designation is done in the context of the whole compound and not in the context of the substituent or asymmetric centre alone.
The designation xe2x80x9cP1, P2, and P3xe2x80x9d as used herein refer to the position of the amino acid residues starting from the C-terminus end of the peptide analogs and extending towards the N-terminus (i.e. P1 refers to position 1 from the C-terminus, P2: second position from the C-terminus, etc.) (see Berger A. and Schechter I., Transactions of the Royal Society London series B257, 249-264 (1970)).
As used herein the term xe2x80x9cvinyl-ACCAxe2x80x9d refers to a compound of formula: 
namely, (1R,2S)1-amino-2-ethenylcyclopropylcarboxylic acid. The term xe2x80x9c(C1-8)alkylxe2x80x9d as used herein, either alone or in combination with another substitutent, means acyclic straight or branched alkyl substituents containing for 1 to 8 carbon atoms and includes, for example, methyl, ethyl, 2-methylhexyl, 1,1-dimethylhexyl (or t-butyl) and octyl.
The term xe2x80x9c(C3-7)cycloalkylxe2x80x9d as used herein, either alone or in combination with another substituent, means a cycloalkyl substituent containing from 3 to 7 carbon atoms and includes cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl.
The term xe2x80x9c{(C1-6)alkyl-(C3-6)cycloalkyl}xe2x80x9d as used herein means a cycloalkyl radical containing from 3 to 6 carbon atoms directly linked to an alkylene radical containing 1 to 6 carbon atoms; for example, cyclopropylmethyl, cyclopentylethyl, cyclohexylmethyl, and cyclohexylethyl. In the instance where R1A is a {(C1-6)alkyl-(C3-6)cycloalkyl}, this group is attached to the SO2 group via the (C1-6)alkyl (i.e. the alkylene portion).
The term xe2x80x9cC6 or C10 arylxe2x80x9d as used herein, either alone or in combination with another radical, means either an aromatic monocyclic group containing 6 carbon atoms or an aromatic bicyclic group containing 10 carbon atoms. For example, aryl includes phenyl, 1-naphthyl or 2-naphthyl.
The term xe2x80x9cOxe2x80x94(C1-6) alkylxe2x80x9d as used herein, either alone or in combination with another radical, means the radical xe2x80x94Oxe2x80x94(C1-6)alkyl wherein alkyl is as defined above containing up to six carbon atoms, and includes methoxy, ethoxy, propoxy, 1-methylethoxy, butoxy and 1,1-dimethylethoxy. The latter radical is known commonly as tert-butoxy.
The term xe2x80x9chaloxe2x80x9d as used herein means a halogen substituent selected from bromo, chloro, fluoro or iodo.
The term xe2x80x9cpharmaceutically acceptable saltxe2x80x9d means a salt of a compound of formula (1) which is, within the scope of sound medical judgment, suitable for use in contact with the tissues of humans and lower animals without undue toxicity, irritation, allergic response, and the like, commensurate with a reasonable benefit/risk ratio, generally water or oil-soluble or dispersible, and effective for their intended use. The term includes pharmaceutically-acceptable acid addition salts and pharmaceutically-acceptable base addition salts. Lists of suitable salts are found in, e.g., S. M. Birge et al., J. Pharm. Sci., 1977, 66, pp. 1-19, which is hereby incorporated by reference in its entirety.
The term xe2x80x9cpharmaceutically-acceptable acid addition saltxe2x80x9d means those salts which retain the biological effectiveness and properties of the free bases and which are not biologically or otherwise undesirable, formed with inorganic acids such as hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, sulfamic acid, nitric acid, phosphoric acid, and the like, and organic acids such as acetic acid, trichloroacetic acid, trifluoroacetic acid, adipic acid, alginic acid, ascorbic acid, aspartic acid, benzenesulfonic acid, benzoic acid, 2-acetoxybenzoic acid, butyric acid, camphoric acid, camphorsulfonic acid, cinnamic acid, citric acid, digluconic acid, ethanesulfonic acid, glutamic acid, glycolic acid, glycerophosphoric acid, hemisulfic acid, heptanoic acid, hexanoic acid, formic acid, fumaric acid, 2-hydroxyethanesulfonic acid (isethionic acid), lactic acid, maleic acid, hydroxymaleic acid, malic acid, malonic acid, mandelic acid, mesitylenesulfonic acid, methanesulfonic acid, naphthalenesulfonic acid, nicotinic acid, 2-naphthalenesulfonic acid, oxalic acid, pamoic acid, pectinic acid, phenylacetic acid, 3-phenylpropionic acid, picric acid, pivalic acid, propionic acid, pyruvic acid, salicylic acid, stearic acid, succinic acid, sulfanilic acid, tartaric acid, p-toluenesulfonic acid, undecanoic acid, and the like.
The term xe2x80x9cpharmaceutically-acceptable base addition saltxe2x80x9d means those salts which retain the biological effectiveness and properties of the free acids and which are not biologically or otherwise undesirable, formed with inorganic bases such as ammonia or hydroxide, carbonate, or bicarbonate of ammonium or a metal cation such as sodium, potassium, lithium, calcium, magnesium, iron, zinc, copper, manganese, aluminum, and the like. Particularly preferred are the ammonium, potassium, sodium, calcium, and magnesium salts. Salts derived from pharmaceutically-acceptable organic nontoxic bases include salts of primary, secondary, and tertiary amines, quaternary amine compounds, substituted amines including naturally occurring substituted amines, cyclic amines and basic ion-exchange resins, such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, isopropylamine, tripropylamine, tributylamine, ethanolamine, diethanolamine, 2-dimethylaminoethanol, 2-diethylaminoethanol, dicyclohexylamine, lysine, arginine, histidine, caffeine, hydrabamine, choline, betaine, ethylenediamine, glucosamine, methylglucamine, theobromine, purines, piperazine, piperidine, N-ethylpiperidine, tetramethylammonium compounds, tetraethylammonium compounds, pyridine, N,N-dimethylaniline, N-methylpiperidine, N-methylmorpholine, dicyclohexylamine, dibenzylamine, N,N-dibenzylphenethylamine, 1-ephenamine, N,Nxe2x80x2-dibenzylethylenediamine, polyamine resins, and the like. Particularly preferred organic nontoxic bases are isopropylamine, diethylamine, ethanolamine, trimethylamine, dicyclohexylamine, choline, and caffeine.
The term xe2x80x9cantiviral agentxe2x80x9d as used herein means an agent (compound or biological) that is effective to inhibit the formation and/or replication of a virus in a mammal. This includes agents that interfere with either host or viral mechanisms necessary for the formation and/or replication of a virus in a mammal. Antiviral agents include, for example, ribavirin, amantadine, VX-497 (merimepodib, Vertex Pharmaceuticals), VX-498 (Vertex Pharmaceuticals), Levovirin, Viramidine, Ceplene (maxamine), XTL-001 and XTL-002 (XTL Biopharmaceuticals).
The term other anti-HCV agent as used herein means those agents that are effective for diminishing or preventing the progression of hepatitis C related symptoms of disease. Such agents can be selected from: antiviral agents, immunomodulatory agents, inhibitors of HCV NS3 protease, inhibitors of HCV polymerase or inhibitors of another target in the HCV life cycle.
The term xe2x80x9cimmunomodulatory agentxe2x80x9d as used herein means those agents (compounds or biologicals) that are effective to enhance or potentiate the immune system response in a mammal. Immunomodulatory agents include, for example, class I interferons (such as xcex1-, xcex2- and omega interferons, tau-interferons, consensus interferons and asialo-interferons), class II interferons (such as xcex3-interferons) and pegylated interferons.
The term xe2x80x9cinhibitor of HCV NS3 proteasexe2x80x9d as used herein means an agent (compound or biological) that is effective to inhibit the function of HCV NS3 protease in a mammal. Inhibitors of HCV NS3 protease include, for example, those compounds described in WO 99/07733, WO 99/07734, WO 00/09558, WO 00/09543, WO 00/59929 or WO 02/060926, and the Vertex/Eli Lilly pre-development candidate identified as VX-950 or LY-570310. Particularly, compounds #2, 3, 5, 6, 8, 10, 11, 18, 19, 29, 30, 31, 32, 33, 37, 38, 55, 59, 71, 91, 103, 104, 105, 112, 113, 114, 115, 116, 120, 122, 123, 124, 125, 126 and 127 disclosed in the table of pages 224-226 in WO 02/060926, can be used in combination with the compounds of the present invention.
The term xe2x80x9cinhibitor of HCV polymerasexe2x80x9d as used herein means an agent (compound or biological) that is effective to inhibit the function of an HCV polymerase in a mammal. This includes, for example, inhibitors of HCV NS5B polymerase. Inhibitors of HCV polymerase include non-nucleosides, for example, those compounds described in:
U.S. application Ser. No. 10/198,680, herein incorporated by reference in its entirety, which corresponds to PCT/CA02/01127, both filed Jul. 18, 2002 (Boehringer Ingelheim),
U.S. application Ser. No. 10/198,384, herein incorporated by reference in its entirety, which corresponds to PCT/CA02/01128, both filed Jul. 18, 2002 (Boehringer Ingelheim),
U.S. application Ser. No. 10/198,259, herein incorporated by reference in its entirety, which corresponds to PCT/CA02/01129, both filed Jul. 18, 2002 (Boehringer Ingelheim),
WO 02/100846 A1 and WO 02/100851 A2 (both Shire),
WO 01/85172 A1 and WO 02/098424 A1 (both GSK),
WO 00/06529 and WO 02/06246 A1 (both Merck),
WO 01/47883 and WO 03/000254 (both Japan Tobacco) and
EP 1 256 628 A2 (Agouron).
Furthermore other inhibitors of HCV polymerase also include nucleoside analogs, for example, those compounds described in:
WO 01/90121 A2 (Idenix),
WO 02/069903 A2 (Biocryst Pharmaceuticals Inc.), and
WO 02/057287 A2 and WO 02/057425 A2 (both Merck/Isis).
Specific examples of inhibitors of an HCV polymerase, include JTK-002, JTK-003 and JTK-109 (Japan Tobacco).
The term xe2x80x9cinhibitor of another target in the HCV life cyclexe2x80x9d as used herein means an agent (compound or biological) that is effective to inhibit the formation and/or replication of HCV in a mammal other than by inhibiting the function of the HCV NS3 protease or HCV polymerase. This includes agents that interfere with either host or HCV viral mechanisms necessary for the formation and/or replication of HCV in a mammal. Inhibitors of another target in the HCV life cycle include, for example, agents that inhibit a target selected from a helicase, an HCV NS2/3 protease and an inhibitor of internal ribosomal entry site (IRES). Specific examples of inhibitors of another target in the HCV life cycle include JTK-003/002 (Japan Tobacco) and ISIS-14803 (ISIS Pharmaceuticals).
The term xe2x80x9cHIV inhibitorxe2x80x9d as used herein means an agents (compound or biological) that is effective to inhibit the formation and/or replication of HIV in a mammal. This includes agents that interfere with either host or viral mechanisms necessary for the formation and/or replication of HIV in a mammal. HIV inhibitors include, for example, nucleosidic inhibitors, non-nucleosidic inhibitors, protease inhibitors, fusion inhibitors and integrase inhibitors.
The term xe2x80x9cHAV inhibitorxe2x80x9d as used herein means an agent (compound or biological) that is effective to inhibit the formation and/or replication of HAV in a mammal. This includes agents that interfere with either host or viral mechanisms necessary for the formation and/or replication of HAV in a mammal. HAV inhibitors include Hepatitis A vaccines, for example, Havrix(copyright) (GlaxoSmithKline), VAQTA(copyright) (Merck) and Avaxim(copyright) (Aventis Pasteur).
The term xe2x80x9cHBV inhibitorxe2x80x9d as used herein means an agent (compound or biological) that is effective to inhibit the formation and/or replication of HBV in a mammal. This includes agents that interfere with either host or viral mechanisms necessary for the formation and/or replication of HBV in a mammal. HBV inhibitors include, for example, agents that inhibit HBV viral DNA polymerase or HBV vaccines. Specific examples of HBV inhibitors include Lamivudine (Epivir-HBV(copyright)), Adefovir Dipivoxil, Entecavir, FTC (Coviracil(copyright)), DAPD (DXG), L-FMAU (Clevudine(copyright)), AM365 (Amrad), Ldt (Telbivudine), monoval-LdC (Valtorcitabine), ACH-126,443 (L-Fd4C) (Achillion), MCC478 (Eli Lilly), Racivir (RCV), Fluoro-L and D nucleosides, Robustaflavone, ICN 2001-3 (ICN), Bam 205 (Novelos), XTL-001 (XTL), Imino-Sugars (Nonyl-DNJ) (Synergy), HepBzyme; and immunomodulator products such as: interferon alpha 2b, HE2000 (Hollis-Eden), Theradigm (Epimmune), EHT899 (Enzo Biochem), Thymosin alpha-1 (Zadaxin(copyright)), HBV DNA vaccine (PowderJect), HBV DNA vaccine (Jefferon Center), HBV antigen (OraGen), BayHep B(copyright) (Bayer), Nabi-HB(copyright) (Nabi) and Anti-hepatitis B (Cangene); and HBV vaccine products such as the following: Engerix B, Recombivax HB, GenHevac B, Hepacare, Bio-Hep B, TwinRix, Comvax, Hexavac.
The term xe2x80x9cclass I interferonxe2x80x9d as used herein means an interferon selected from a group of interferons that all bind to receptor type I. This includes both naturally and synthetically produced class I interferons. Examples of class I interferons include xcex1-, xcex2, omega interferons, tau-interferons, consensus interferons, asialo-interferons.
The term xe2x80x9cclass II interferonxe2x80x9d as used herein means an interferon selected from a group of interferons that all bind to receptor type II. Examples of class II interferons include xcex3-interferons.
The pharmaceutical compositions of the invention may contain one or more additional active agents selected, for example, from antiviral agents, immunomodulatory agents, other inhibitors of HCV NS3 protease, inhibitors of HCV polymerase or inhibitors of another target in the HCV life cycle, HIV inhibitors, HAV inhibitors and HBV inhibitors. Examples of such agents are provided in the Definitions section above.
Specific preferred examples of some of these agents are listed below:
antiviral agents: ribavirin and amantadine;
immunomodulatory agents: class I interferons, class II interferons and pegylated interferons;
inhibitor of another target in the HCV life cycle that inhibits a target selected from: NS3 helicase, HCV NS2/3 protease or internal ribosome entry site (IRES);
HIV inhibitors: nucleosidic inhibitors, non-nucleosidic inhibitors, protease inhibitors, fusion inhibitors and integrase inhibitors; or
HBV inhibitors: agents that inhibit HBV viral DNA polymerase or is an HBV vaccine.
As discussed above, combination therapy is contemplated wherein a compound of formula (1), or a pharmaceutically acceptable salt thereof, is co-administered with at least one additional agent selected from: an antiviral agent, an immunomodulatory agent, another inhibitor of HCV NS3 protease, inhibitor of HCV polymerase, an inhibitor of another target in the HCV life cycle, an HIV inhibitor, an HAV inhibitor and an HBV inhibitor. Examples of such agents are provided in the Definitions section above. These additional agents may be combined with the compounds of this invention to create a single pharmaceutical dosage form. Alternatively these additional agents may be separately administered to the patient as part of a multiple dosage form, for example, using a kit. Such additional agents may be administered to the patient prior to, concurrently with, or following the administration of wherein a compound of formula (1), or a pharmaceutically acceptable salt thereof.
As used herein, the term xe2x80x9ctreatmentxe2x80x9d means the administration of a compound or composition according to the present invention to alleviate or eliminate symptoms of the hepatitis C disease and/or to reduce viral load in a patient.
As used herein, the term xe2x80x9cpreventionxe2x80x9d means the administration of a compound or composition according to the present invention post-exposure of the individual to the virus but before the appearance of symptoms of the disease, and/or prior to the detection of the virus in the blood.
Preferably, compounds of formula 1 as defined above wherein R1 is hydroxy, NHSO2Me, NHSO2cyclopropyl or NHSO2Ph. More preferably, R1 is NHSO2-cyclopropyl or NHSO2Ph. Alternatively, most preferably, R1 is hydroxy.
Preferably, compounds of formula 1 as defined above wherein R2 is cyclopentyl or cyclohexyl. Most preferably, R2 is cyclopentyl.
Preferably, R3 is t-butyl or cyclohexyl. Most preferably, R3 is t-butyl.
Preferably, compounds of formula 1 as defined above wherein R4 is cyclobutyl or cyclopentyl. Most preferably, R4 is cyclopentyl.
More preferably, a compound of formula 1 as defined above wherein R1 is hydroxy, R2 and R4 each is cyclopentyl and R3 is t-butyl.
More preferably, a compound of formula 1 wherein R1 is hydroxy, R2 is cyclobutyl, R3 is t-butyl and R4 is cyclopentyl.
More preferably, a compound of formula 1 wherein R1 is hydroxy, R2 is cyclohexyl, R3 is t-butyl and R4 is cyclopentyl.
More preferably R1 is NHSO2Ph, R2 and R4 each is cyclopentyl and R3 t-butyl.
More preferably, a compound of formula 1 wherein R1 is hydroxy, R2 is cyclopentyl, R3 is t-butyl and R4 is cyclobutyl.
More preferably, a compound of formula 1 wherein R1 is hydroxy, R2 is cyclopentyl, R3is t-butyl and R4 is cyclohexyl.
More preferably, a compound of formula 1 wherein R1 is hydroxy, R2 and R4 each is cyclopentyl and R3 is cyclohexyl.
More preferably, a compound of formula 1 wherein R1 is hydroxy, R2, R3 and R4 each is cyclopentyl.
According to an alternate embodiment, the pharmaceutical composition of this invention may additionally comprise another anti-HCV agent. Examples of anti-HCV agents include, xcex1-(alpha), xcex2-(beta), xcex4-(delta), xcex3-(gamma) or xcfx89-(omega) interferon, ribavirin and amantadine.
According to another alternate embodiment, the pharmaceutical composition of this invention may additionally comprise another inhibitor of HCV NS3 protease.
According to another alternate embodiment, the pharmaceutical composition of this invention may additionally comprise an inhibitor of HCV polymerase.
According to yet another alternate embodiment, the pharmaceutical composition of this invention may additionally comprise an inhibitor of other targets in the HCV life cycle, including but not limited to, helicase, NS2/3 protease or internal ribosome entry site (IRES).
The pharmaceutical composition of this invention may be administered orally, parenterally or via an implanted reservoir. Oral administration or administration by injection is preferred. The pharmaceutical composition of this invention may contain any conventional non-toxic pharmaceutically-acceptable carriers, adjuvants or vehicles. In some cases, the pH of the formulation may be adjusted with pharmaceutically acceptable acids, bases or buffers to enhance the stability of the formulated compound or its delivery form. The term parenteral as used herein includes subcutaneous, intracutaneous, intravenous, intramuscular, intra-articular, intrasynovial, intrasternal, intrathecal, and intralesional injection or infusion techniques.
The pharmaceutical composition may be in the form of a sterile injectable preparation, for example, as a sterile injectable aqueous or oleaginous suspension. This suspension may be formulated according to techniques known in the art using suitable dispersing or wetting agents (such as, for example Tween 80) and suspending agents.
The pharmaceutical composition of this invention may be orally administered in any orally acceptable dosage form including, but not limited to, capsules, tablets, and aqueous suspensions and solutions. In the case of tablets for oral use, carriers which are commonly used include lactose and corn starch. Lubricating agents, such as magnesium stearate, are also typically added. For oral administration in a capsule form, useful diluents include lactose and dried corn starch. When aqueous suspensions are administered orally, the active ingredient is combined with emulsifying and suspending agents. If desired, certain sweetening and/or flavoring and/or coloring agents may be added.
Other suitable vehicles or carriers for the above noted formulations and compositions can be found in standard pharmaceutical texts, e.g. in xe2x80x9cRemington""s Pharmaceutical Sciencesxe2x80x9d, The Science and Practice of Pharmacy, 19th Ed. Mack Publishing Company, Easton, Pa., (1995).
Dosage levels of between about 0.01 and about 100 mg/kg body weight per day, preferably between about 0.1 and about 50 mg/kg body weight per day of the protease inhibitor compound described herein are useful in a monotherapy for the prevention and treatment of HCV mediated disease. Typically, the pharmaceutical composition of this invention will be administered from about 1 to about 5 times per day or alternatively, as a continuous infusion. Such administration can be used as a chronic or acute therapy. The amount of active ingredient that may be combined with the carrier materials to produce a single dosage form will vary depending upon the host treated and the particular mode of administration. A typical preparation will contain from about 5% to about 95% active compound (w/w). Preferably, such preparations contain from about 20% to about 80% active compound.
As the skilled artisan will appreciate, lower or higher doses than those recited above may be required. Specific dosage and treatment regimens for any particular patient will depend upon a variety of factors, including the activity of the specific compound employed, the age, body weight, general health status, sex, diet, time of administration, rate of excretion, drug combination, the severity and course of the infection, the patient""s disposition to the infection and the judgment of the treating physician. Generally, treatment is initiated with small dosages substantially less than the optimum dose of the peptide. Thereafter, the dosage is increased by small increments until the optimum effect under the circumstances is reached. In general, the compound is most desirably administered at a concentration level that will generally afford antivirally effective results without causing any harmful or deleterious side effects.
When the composition of this invention comprise a combination of a compound of formula 1 and one or more additional therapeutic or prophylactic agent, both the compound and the additional agent should be present at dosage levels of between about 10 to 100%, and more preferably between about 10 and 80% of the dosage normally administered in a monotherapy regimen.
When these compounds or their pharmaceutically acceptable salts are formulated together with a pharmaceutically acceptable carrier, the resulting composition may be administered in vivo to mammals, such as man, to inhibit HCV NS3 protease or to treat or prevent HCV virus infection. Such treatment may also be achieved using a compound of this invention in combination with agents which include, but are not limited to: xcex1-, xcex2-, xcex4-, xcfx89-, or xcex3-interferon, ribavirin, amantadine; other inhibitors of HCV NS3 protease; inhibitors of HCV polymerase; inhibitors of other targets in the HCV life cycle, which include but not limited to, helicase, NS2/3 protease, or internal ribosome entry site (IRES); or combinations thereof. The additional agents may be combined with compounds of this invention to create a single dosage form. Alternatively these additional agents may be separately administered to a mammal as part of a multiple dosage form.
Accordingly, another embodiment of this invention provides a method of inhibiting HCV NS3 protease activity in a mammal by administering a compound of the formula 1.
In a preferred embodiment, this method is useful in decreasing the NS3 protease activity of the hepatitis C virus infecting a mammal.
If the pharmaceutical composition comprises only a compound of this invention as the active component, such method may additionally comprise the step of administering to said mammal an agent selected from an immunomodulatory agent, an antiviral agent, a HCV NS3 protease inhibitor, an inhibitor of HCV polymerase or an inhibitor of other targets in the HCV life cycle such as helicase, NS2/3 protease or IRES. Such additional agent may be administered to the mammal prior to, concurrently with, or following the administration of the composition of this invention.
A compound of formula 1 set forth herein may also be used as a laboratory reagent. A compound of this invention may also be used to treat or prevent viral contamination of materials and therefore reduce the risk of viral infection of laboratory or medical personnel or patients who come in contact with such materials (e.g. blood, tissue, surgical instruments and garments, laboratory instruments and garments, and blood collection apparatuses and materials).
A compound of formula 1 set forth herein may also be used as a research reagent. A compound of formula 1 may also be used as positive control to validate surrogate cell-based assays or in vitro or in vivo viral replication assays.
Further details of the invention are illustrated in the following examples which are understood to be non-limiting with respect to the appended claims.
In general, the compounds of formula 1, and intermediates therefore, are prepared by known methods using reaction conditions which are known to be suitable for the reactants. Several such methods are disclosed in WO 00/09543, WO 00/09558 and U.S. Pat. No. 6,323,180, incorporated herein by reference.
Compounds of formula I wherein R1 is NHSO2R1A as defined herein are prepared by coupling the corresponding acid of formula I (i.e. R1 is hydroxy) with an appropriate sulfonamide of formula R1A SO2NH2 in the presence of a coupling agent under standard conditions. Although several commonly used coupling agents can be employed, TBTU and HATU have been found to be practical. The sulfonamides are available commercially or can be prepared by known methods.
The following schemes illustrate two convenient processes using known methods for preparing the compounds of formula 1 when R1 is OH. 